Anyone peen the rails on an auto?

[trotterlg]

Have any of you peened the rails on an old automatic to tighten it up some?  I've got a nice old Spanish 25 auto, good function but really loose, it would be nice to take a little play out of the slide.  Should I peen the slide or the frame, I know not to do both.  Any pictures?  Larry

[Luckyducker]

I have never heard of anybody peening the rails to tighten up the action.  I have heard of peening or stoning the battered guide rails on Remington auto rifles (30/06) to fascilitate cycling.  That doesn't mean it hasn't been done, it just means I have never heard of it.

[gunnut69]

I've used the technique on 1911 to tighten frame/slide fit but never a 25 auto.. The rule of thumb is to alter the least costly part.. I used a guage plate ground flat to set the gap in the slide rails and tapped them even. The frame was first measured of course to accertain the grove and rail tolerances.. To tighten the horizontal fit the slide was lightly squeezed in a fixture held in the vice.. A metal guage again provided safety to avoid over tightening. Pachmeyer (I think,,CRS) developed a system using precisely sized rods with their ends bent to fit in holes for retension to takeup the slack. This allowed for replacement and retightening of worn components..

[Arizona Jake]

I USED THE TECHNIQUE ON MY SPRINGFIELD ARMORY P9 IN .45 ACP WITH VERY GOOD RESULTS. IT SHRUNK 50 FT. 3-SHOT GROUPS FROM 3 INCHES TO 1 INCH.

[spruce]

Never done it, but I know it used to be a common procedure used for accurizing 1911's - especially popular with bullseye shooters.

If you can find any older books on accurizing the 1911 it's probably covered.  You might check in the Kuhnhausen (sp?) manual - don't know if he covered it or not.

[trotterlg]

I'm starting to get an idea about how to go about it from you guys, also the part about squeezing the slide some to tighten up that direction.  I think I will make up a punch with a little sholder on it to hold it in the same place on the rail and then just work my way down the length of the slide.  When I get going I will try to take some pictures, I don't think these things were that tight even 70 years ago when they were built.  Larry

[gunnut69]

There are a lot of things to think about before proceeding on with the project. Slide squeezing is to tighten dimensions left to right or horizontally, peening tightens mainly in fit of slide to frame.. When squeezing down a slide it is most appropriate to have a stop between the rails to limit the slides closure. Limiting the peening process is more difficult but precision machined paralells are avaiable in various thicknesses to limit the movement of the metal.. Also I strongly advise that any peening be done using punches as they provide much greater control of the hits and their direction.. Proceed with great caution here as a mistep can be very expensive.